This blog post may sound challenging, but to make our case, we will rely on the most efficient technology we know to date: Solid Oxide technology.
Solid Oxide Electrolysis (SOE) was demonstrated by Dornier and Lurgi in the 1980s, and since then, research and development have continued. If we think about it carefully, Solid Oxide (SO) has been in development for 40 years and continues to evolve. It still has much to improve and offer to the high-temperature electrolyzer market.
In 2017, the European Commission established the electrical consumption, the state-of-the-art of the technology, at 41 kWh/kg. This corresponds to an efficiency of just over 81% based on the LHV (Lower Heating Value). By 2030, it is expected to reach a value of 37 kWh/kg, which translates to 90% efficiency.
To achieve these high efficiency values, SO technology “plays” with the thermodynamics of the electrolysis reaction. First, it moves from the liquid phase to the vapor phase, reducing the reaction enthalpy, and then it shifts to the right (see figure) to have more heat component and less work (electricity) component. The reaction enthalpy remains more or less constant along the X-axis (temperature), so the higher the temperature, the less electricity is needed to break the molecule, and the more efficiency can be achieved.
As you all know, playing with thermodynamics is expensive; high-temperature electrolyzers are still costly and less durable compared to their liquid water counterparts. But we’re not here to judge this technology (which we love!), but rather to use it as a reference to answer the initial question: Why is it hard to believe that a company has made an electrolyzer with 95% efficiency? Because if the most thermodynamically advanced technology has been in development for 40 years and has only just surpassed 80%, it’s hard to believe that now, with all the interest in renewable hydrogen, in just a couple of years, someone has achieved 95% efficiency (by LHV or HHV, by the way). If it were true, when would it be ready-to-market?
We hope this thought gets challenged, but still, we should take all the news coming out today with caution. In almost a decade of working exclusively in the renewable hydrogen sector, we have often heard and read about miraculous formulas, but in the end, the same technologies remain. Are we witnessing a new generation of electrolyzers? Time will tell.
If you found this blog post interesting, follow us on LinkedIn, and you won’t miss our new post every week.
Lean Hydrogen is an engineering and consulting firm specializing in renewable hydrogen technologies. Visit our website: www.leanhydrogen.com to learn more about us.
Image by: Thorsteinn Sigfusson
